The present invention relates to a system for supplying a gas to be stored in a vessel which releases the gas at the time of vehicle impact or collision to inflate a vehicle occupant restraint such as an air bag, and particularly to a system for supplying the gas and then weld-sealing the opening through which it is supplied. Typically, such bags are not inflated with air but, rather, nitrogen, carbon dioxide or helium. Normally such a vessel or canister also houses a gas-generating material separately from the stored, highly pressurized gas. A typical gas-generating material may comprise a halogen free alkali metal salt, an inorganic oxidizer, and a polyvinyl chloride binder which is ignited when a sensor discerns an imminent collision and the need for inflation of the bag. The generated gas ruptures a seal and is typically directed into the pressurized stored gas, with the pressure of the stored gas and the generated gas rupturing a second seal, which then permits the flow of the commingled gases into the inflatable device. An igniter material is provided within the canister to produce, typically, the heated gas to mix with the stored nitrogen gas. While, previously, systems for supplying a weldable ball to a weldable shock absorber chamber, having a specially configured opening pierced in its external casing wall, have been produced, as demonstrated, for instance, in the present assignee's European Patent application 83109775.3, filed Sep. 29, 1983 and published as No. 0107102, it should be understood that the pressure of the nitrogen gas supplied to the shock absorber chamber is much less than the pressure of the nitrogen gas which needs to be supplied to an air bag vessel or container. For example, the gas under pressure supplied to a shock absorber, is in the nature of 150 PSI, whereas the gas which is supplied to an air bag canister is in the nature of 3700 PSI. This very considerable difference in pressure renders systems which have been suitable for manufacturing shock absorbers, unsuited to the manufacture of air bag canisters. The above identified European patent publication, and the following list of patents, are exemplary of the prior art systems which have been employed, and are incorporated by reference herein:
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